Specific ζ-Potential Response of Layer-by-Layer Coated Colloidal Particles Triggered by Polyelectrolyte Ion Interactions

• Published in: Langmuir Vol. 25; no. 6; pp. 3374 - 3380
• Main Authors: Irigoyen, J, Moya, S. E, Iturri, J. J, Llarena, I, Azzaroni, O, Donath, E
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 17-03-2009
• Subjects: Amines - chemistry; Chemistry; Colloidal state and disperse state; Colloids - chemistry; Colloids: Surfactants and Self-Assembly, Dispersions, Emulsions, Foams; Crystallization; Electrolytes - chemistry; Exact sciences and technology; General and physical chemistry; Hydrogen Bonding; Ions; Materials Testing; Microscopy, Atomic Force - methods; Particle Size; Physical and chemical studies. Granulometry. Electrokinetic phenomena; Polyethylenes - chemistry; Quartz; Quaternary Ammonium Compounds - chemistry; Salts - chemistry; Silicon Dioxide; Sodium Chloride - chemistry; Surface physical chemistry; Surface Properties; Phosphates; Atomic force microscopy; Binary compound; Surface charge; Stability; Hydrogen; Crystals; Ions; Silica; Polyelectrolyte; Coated particle; Electrokinetic potential; Primary amine; Colloid particle; Quartz microbalance
• ISSN: 0743-7463; 1520-5827
• DOI: 10.1021/la803360n

The ζ-potential of PSS/PAH and PSS/PDADMAC coated silica particles was studied in the presence of ClO4 − and H2PO4 − salts. In the presence of ClO4 −, layer-by-layer (LbL) coated silica particles with PDADMAC as the top layer show a reversal in the surface charge with increasing salt concentration but remain positive in phosphate solutions. LbL particles with PAH as the top layer become, however, negative in the presence of H2PO4 − but retain their positive charge in the presence of ClO4 −. Charge reversal was explained by specific interaction of ClO4 − ions with the quaternary amine groups and of H2PO4 − with the primary amines through hydrogen bonding. Atomic force microscopy (AFM) and quartz crystal microbalance with dissipation (QCM-D) were employed to study the corresponding layer stability on planar surfaces.